The Obama administration’s top intelligence official acknowledged Friday that there have been “a number of compliance problems” in the government program that has collected phone data on millions of Americans.

James Clapper, director of national intelligence, also said the government had not collected any other bulk data on Americans using its authority under the USA Patriot Act beyond the phone information and Internet data gathered under a separate program that was canceled in 2011.

Clapper made the statements in a four-page letter responding to a series of questions posed to him last month by a bipartisan group of 26 senators.

The lawmakers, accusing the Obama administration of making misleading statements in the past regarding the records it was collecting with the permission of the Foreign Intelligence Surveillance Court, had asked Clapper to list any “violations of the court orders permitting this bulk collection, or of the rules governing access to these records.”

Since the leaked disclosure of the phone data program last month by former National Security Agency contractor Edward Snowden, administration officials have assured lawmakers that internal checks are in place to restrict access. And they said the government can search the data only if there is a “reasonable, articulable suspicion that the phone number being searched is associated with certain terrorist organizations,” as Deputy Attorney General James Cole told House members this month.

In the letter, released Friday by Sen. Ron Wyden (D-Ore.), a vocal critic of the surveillance program, Clapper said the problems had been “previously identified and detailed in reports to the Court and briefings to Congress. ”

“However, there have been no findings of any intentional or bad-faith violations,” he wrote. “These problems generally involved human error or highly sophisticated technology issues related to NSA’s compliance with particular aspects of the Court’s orders.”

Clapper’s letter did not provide details but offered to give lawmakers more information in a classified setting. A spokesman for Clapper declined to elaborate.

Wyden, in an interview late Friday, said intelligence officials could “definitely” reveal more information about the problems without compromising national security. As a member of the Senate Intelligence Committee, Wyden said he was aware of the details but could not disclose them because of classification rules. “The intelligence agencies constantly come back to the refrain about how careful they are,” he said. “This certainly raises substantial questions about that argument.”

Wyden has warned in the past that the court’s secret interpretations of the Patriot Act gave the government the authority to collect other forms of bulk data, including health information and credit card records.

In response to Clapper’s denial that additional bulk data was being collected, Wyden said, as he has before, that the government’s authority is “limitless.”

Clapper pushed back against previous assertions by Wyden that a secret reinterpretation of law allowed the bulk collection. He described underlying legal opinions as “properly classified.”

Wyden said: “That just takes your breath away.”